In substrates with transparent electrodes, which are used in display devices such as touch panels and displays, light-emitting devices such as LEDs, and light-receiving devices such as solar cells, control of electrical properties so called sheet resistance is important. A transparent conductive oxide including indium oxide as a main component is often used as a material of such transparent electrodes. The addition of metal oxides such as tin oxide to the indium oxide enables imparting of various properties.
There has been known, as the structure of a common substrate with transparent electrodes, those in which a transparent electrode thin film is formed on a soft substrate such as a film and patterning is carried out. To perform crystallization, transparent conductive oxide such as indium oxide is required to undergo high-temperature deposition or a heat treatment after the deposition, and the temperature is determined by heat resistance of the film substrate and the transparent conductive oxide has poor conductivity as compared with that of metal. Inevitably, it is considered that electrical properties of the transparent electrode using a transparent conductive oxide have limits, for example, 8×10−5 to 3×10−4 Ωcm.
Meanwhile, there have been developed, as a material for low-resistance transparent electrodes, resins including metal nanowires dispersed therein, metal mesh, and the like, and activities towards the practical application have been intensively promoted. Particularly, as mentioned in Patent Document 1, a mesh-like and translucent (transparent) mesh metal is obtained by using, as metal wiring, a thin wire having a line width of 10 μm or less, especially 5 μm or less.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2013-186632
Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2008-311565
Patent Document 3: Japanese Unexamined Patent Application, Publication No. 2002-246788
Patent Document 4: Japanese Unexamined Patent Application, Publication No. H10-307204